Part size

Zinc arc spraying is an inexpensive process in terms of equipment and raw materials. Only 55—110 g/m is required for a standard 0.05—0.10 mm Zn thickness. It is more labor intensive, however. Grit blasting is a slow process, at a rate of 4.5 m /h. AppHcation of an adhesive paint layer is much quicker, 24 m /h, although the painted part must be baked or allowed to air dry. Arc sprayed 2inc is appHed at a rate of 9—36 m /h to maintain the plastic temperature below 65°C. The actual price of the product depends on part complexity, number of parts, and part size. A typical price in 1994 was in the range of 10—32/m. ... 

Product design factors overall part size shape complexity critical dimensions weight limitations potential for parts integration assembly requirements secondary operations Materialfactors... 

Mold temperatures vary between 150—200°C, depending on the mol ding methods and part size. Parts can be molded in 1.5—10 min depending on the configuration and thickness of the part, the mold temperature, and the desired state of cure at demolding. Since most ethylene—acryflc parts are postcured, it is sometimes possible to demold partly cured articles and complete vulcanization in the postcuring oven. 

All types of mol ding may be carried out at 150 to 200°C. This allows mol ding times of five minutes or less for most fluorocarbon elastomer parts, but this time is dependent on part size. 

S.2.2.2. Composite adherends. Composite adherends are bonded in both the cured and uncured states. Wherever possible the adhesive and all adherends are cured simultaneously to avoid the added cost of additional autoclave cure cycles. In many cases this is not practical due to part size and complexity. Cured parts can be bonded to uncured parts, which is known as cobonding, and fully cured parts can be bonded together, which is known as secondary bonding. Adhesives for composites are formulated to be compatible with matrix resins in either cured or uncured states. 

Mold shrinkage determined on 0.125 X 3 X 6 in molded plaques actual shrinkage will vary with part size and design. Mold shrinkage values for pellethane ... 

Three principal layup processes for laminated fiber-reinforced composite materials are winding, laying, and molding. The choice of a layup process (as well as a curing process) depends on many factors part size and shape, cost, schedule, familiarity with particular techniques, etc. 

The part sizes are limited by the tool sizes such as moulds, dies, autoclaves or winding machines and by the power and the size of equipment such as presses, bags, pultrusion machines, etc. 

Part size, maximum area (m ) Thickness (mm) Examples of parts Smooth surface Method... 

Part sizes are limited by the mould size and the machinery performances. 

The processing methods will be selected according to the importance of the series, part sizes and targeted properties. Table 6.1 suggests some processes, for thermoplastic and thermoset composites, according to the part sizes and production outputs. 

Resin flow models are capable of determining the flow of resin through a porous medium (prepreg and bleeder), accounting for both vertical and horizontal flow. Flow models treat a number of variables, including fiber compaction, resin viscosity, resin pressure, number and orientation of plies, ply drop-off effects, and part size and shape. An important flow model output is the resin hydrostatic pressure, which is critical for determining void formation and growth. 

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